J/A+A/640/A72ivo://CDS.VizieR/J/A+A/640/A72CDSRiener M.Kainulainen J.Henshaw J.D.Beuther H.2026-07-09T18:36:31Z2026-07-09T19:34:00ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frsurveysradio-astronomygalaxy-planesmilky-way-galaxystellar-distancegalaxy-kinematicsinterstellar-mediumKnowledge about the distribution of CO emission in the Milky Way is essential to understand the impact of Galactic environment on the formation and evolution of structures in the interstellar medium. However, currently our insight about the fraction of CO in spiral arm and interarm regions is still limited by large uncertainties in assumed rotation curve models or distance determination techniques. In this work we use the Bayesian approach from Reid et al. (2016ApJ...823...77R) and Reid et al. (2019ApJ...885..131R) that is based on our presently most precise knowledge about the structure and kinematics of the Milky Way to obtain the current best assessment of the Galactic distribution of ^13^CO from the Galactic Ring Survey (GRS). We performed two different distance estimates that either included (Run A) or excluded (Run B) a model for Galactic features, such as spiral arms or spurs. We also include a prior for the solution of kinematic distance ambiguity that was determined from a compilation of literature distances and an assumed size-linewidth relationship. Even though the two distance runs show strong differences due to the prior for Galactic features for Run A and larger uncertainties due to kinematic distances in Run B, the majority of their distance results are consistent with each other within the uncertainties. We find that the fraction of ^13^CO emission associated with spiral arm features varies between 76% to 84% between the two distance runs. The vertical distribution of the gas is concentrated around the Galactic midplane showing full-width at half-maximum values of ~75pc. We do not find any significant difference between gas emission properties associated with spiral arm and interarm features. In particular the distribution of velocity dispersion values of gas emission in spurs and spiral arms is very similar. We detect a trend of higher velocity dispersion values with increasing heliocentric distance, which we however attribute to beam averaging effects caused by differences in spatial resolution. We argue that the true distribution of the gas emission is likely more similar to a combination of the two discussed distance results, and highlight the importance of using complementary distance estimations to safeguard against the pitfalls of any single approach. We conclude that the methodology presented in this work is a good approach for distance determinations of gas emission features in Galactic plane surveys.2020A&A...640A..72Rhttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/640/A72CatalogResearchIsServedByTAP VizieR generic serviceIsServedByConesearch servicerelated-toJ/A+A/633/A14 : GaussPy+ decomposition of Galactic Ring Survey (Riener+, 2020)https://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/A+A/640/A72https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/A+A/640/A72http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/A+A/640/A72https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/A+A/640/A72https://vizier.iucaa.in/viz-bin/votable?-source=J/A+A/640/A72http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/A+A/640/A72GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapCone search capability for table J/A+A/640/A72/table2 (Distance results)https://vizier.cds.unistra.fr/viz-bin/conesearch/J/A+A/640/A72/table2?https://vizier.iucaa.in/viz-bin/conesearch/J/A+A/640/A72/table2?http://vizieridia.saao.ac.za/viz-bin/conesearch/J/A+A/640/A72/table2?GETtext/xml+votable180.050000true273.84645-16.716670.0055555555555555565/3242 7376-7377 7380 7382-7383 7554 7561 7564-7565 7567 7578-7579 7604-7605 7648 7650-7651 7654 7661 7672-7673 7678-7679 6/14336-14337 29114-29115 29118-29119 29162-29163 29166 29456-29457 29460-29461 29513 29516-29517 29526-29527 29556-29557 30220 30222-30223 30234 30240-30241 30243 30253 30264-30265 30306-30307 30310 30328 30330-30331 30334-30335 30400-30401 30404-30405 30407 30428-30429 30598-30599 30610 30620 30622-30623 30629 30640-30641 30666-30667 30696-30697 30700-30701 30703-30704 30706-30707 30710-30711 32084-32085https://cdsarc.cds.unistra.fr/viz-bin/moc/J/A+A/640/A72?format=asciiRadiodefaultJ/A+A/640/A72/table2Distance resultsrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintGLON[14/56] Galactic longitude positiondegpos.galactic.lonindexedGLAT[-1.1/1.1] Galactic latitude positiondegpos.galactic.latindexedVLSRFitted centroid velocity valuekm/sphys.veloc;pos.lsrfloatDistAHeliocentric distance value for BDC Run Akpcpos.distancefloate_DistAUncertainty in distAkpcstat.errorfloatRgalAGalactocentric distance value for BDC Run Akpcpos.distance;stat.value;pos.galactocentricfloatprobA[0/1] Estimated probability value for BDC Run Astat.fit.goodnessfloatArmAAssociated Galactic featuremeta.id.parentcharpfarA[0/1] Probability value for the Pfar priorstat.fit.goodnessfloatr_DistAReference for associated literature distance (1)meta.ref;pos.framecharFlagA[0/4] Flag for the distance choice (2)meta.code.errorintDistBHeliocentric distance value for BDC Run Bkpcpos.distancefloate_DistBUncertainty in distBkpcstat.errorfloatRgalBGalactocentric distance value for BDC Run Bkpcpos.distance;stat.value;pos.galactocentricfloatprobBEstimated probability value for BDC Run Bstat.fit.goodnessfloatArmBAssociated Galactic featuremeta.id.parentcharpfarB[0/1] Probability value for the Pfar priorstat.fit.goodnessfloatr_DistBReference for associated literature distance (1)meta.ref;pos.framecharFlagB[0/4] Flag for the distance choice (2)meta.code.errorint_RA.icrsRight ascension (ICRS) (computed by VizieR, not part of the original data. The format may include more digits than the original data because of internal accuracy requirements in VizieR and across other CDS services)degpos.eq.raindexed_DE.icrsDeclination (ICRS) (computed by VizieR, not part of the original data. The format may include more digits than the original data because of internal accuracy requirements in VizieR and across other CDS services)degpos.eq.decindexed